1. Field of the Invention
The present invention relates to a liquid composition, an ink for ink-jet, an ink set for ink-jet recording, an ink-jet recording method, a recording unit, an ink cartridge, and an ink-jet recording apparatus. In particular, the present invention relates to a liquid composition, which: has water resistance and excellent print quality; reduces color bleeding that occurs in formation of color images; and can extend a life-span of ink-jet recording heads using thermal energy, as well as to an ink for ink-jet, an ink set for ink-jet recording, an ink-jet recording method using one of these, a recording unit, an ink cartridge, and an ink-jet recording apparatus.
2. Description of Background Art
The ink-jet recording method makes it easy to miniaturize an apparatus, to reduce running cost, to colorize, etc., and has the superiority in the formation of color images, although there are some problems under circumstances where improvement of image quality is further required. For example, when two different inks are applied on a recording medium adjacently to each other, there is a problem in that those inks are mixed with each other at the boundary therebetween, and as a consequent, a phenomenon of degradation of color image quality (bleeding) occurs. In particular, since color mixing at the boundary between black ink and color ink has a large effect on the degradation of image quality, various methods for solving the problems have been developed.
For example, as described in Japanese Patent Laid-open No. 5,-202,328, U.S. Pat. No. 5,198,023, and Japanese Patent Laid-Open No. 6-106841, a technique for controlling the color bleeding by concurrent use of a first liquid containing a precipitant and a second liquid containing a coloring agent, which can produce precipitates by the precipitant, has been disclosed. As this precipitant, polyvalent metal salts have been disclosed, and as the coloring agent, which can produce precipitates by the polyvalent metal salts, dyes including at least one carboxylic group, etc., have been disclosed. Furthermore, the first liquid may include the coloring agent, and in this case, the first liquid can also be used as the ink.
However, according to research by the inventors of the present invention, it was discovered that when a solution containing a polyvalent metal salt, as described in Japanese Patent Laid-Open No. 5-202328 in order to prevent the aforementioned bleeding, was repeatedly ejected by a bubble-jet method, sometimes, kogation derived from the polyvalent metal salt were formed on a heater contacting with the solution containing the polyvalent metal salt. As a result, the quantity of the ejected liquid droplets and the speed of the ejected liquid droplets were reduced compared to those at the initial stage so as to cause a problem in that the image quality was affected. In addition, it has been observed that kogation sometimes causes breaks in the heater so as to prevent ejection of the polyvalent metal salt solution.
It is believed that the cause of the aforesaid ejection problems is the overheating of the ink or the liquid composition containing polyvalent metal salts, by the heater, which volatizes or breaks down the anions constituting the polyvalent metal salts, and therefore, increasing the concentration of cation ions (polyvalent metal ions) around the heater. As a result, the alkalinity is also increased causing the outermost surface protection film, typically made of a metal, such as, for example, tantalum, and metal oxides, to dissolve.
Therefore, the inventors of the present invention earnestly researched regarding liquid compositions or inks which: have an effect of alleviating bleeding; prevent breaks of heaters and kogation; and can extend a life-span of recording heads. As a consequence, the present invention has been made. Accordingly, it is an object of the present invention to provide a liquid composition which can extend the life-span of an ink-jet recording head and can form high-quality images when used in an ink-jet recording method together with an ink.
Another object of the present invention is to provide an ink set which can extend the life-span of an ink-jet recording head, and can form high quality images.
A further object of the present invention is to provide an ink-jet recording method, a recording unit, an ink cartridge, and an ink-jet recording apparatus which can provide high quality images and extend the life-span of an ink-jet recording head.
The above objects are achieved by the present invention as described below.
According to one aspect of the present invention, there is provided a liquid composition for ink-jet recording which is used together with a color ink and reacts with the color ink when it comes into contact with the color ink, the liquid composition comprising (a) a polyvalent metal salt, (b) a material selected from the group consisting of acids including amino groups and salts thereof, and (c) a liquid medium.
According to another aspect of the present invention, there is provided an ink-jet recording method comprising the steps of: (i) ejecting aforementioned liquid composition toward a recording medium by applying energy to the liquid composition; and (ii) ejecting aforementioned color ink toward a recording medium by applying energy to the color ink, wherein the steps are performed so that the liquid composition and the color ink form a contact state on the recording medium.
According to further aspect of the present invention, there is provided an ink set for ink-jet recording comprising: (1) the aforementioned liquid composition and (2) a color ink which comprises a coloring material and a liquid medium, and reacts with the liquid composition by contact with the liquid composition.
According to still further aspect of the present invention, there is provided a recording unit comprising: a liquid composition container portion containing the aforementioned liquid composition; an ink container portion containing a color ink which reacts with the liquid composition by contact with said liquid composition; and an ink-jet recording head for ejecting each of the liquid composition and the color ink by applying energy to the liquid composition and the color ink.
According to still further aspect of the present invention, there is provided an ink cartridge comprising: a liquid composition container portion containing the aforementioned liquid composition; and an ink container portion containing a color ink which comprises a coloring material and a liquid medium, and reacts with the liquid composition by contact with the liquid composition.
According to still further aspect of the present invention, there is provided an ink-jet recording apparatus comprising: a liquid composition container portion containing a liquid composition; an ink container portion containing a color ink which reacts with the liquid composition by contact with the liquid composition; and an ink-jet recording head for ejecting each of the liquid composition and the color ink by applying energy to the liquid composition and the color ink, wherein the liquid composition is the aforementioned liquid composition.
According to still further aspect of the present invention, there is provided an ink set for ink-jet recording comprising: (1) a color ink comprising a coloring material, a liquid medium, a polyvalent metal salt, and a material selected from the group consisting of acids including amino groups and salts thereof; and (2) a black ink which comprises a coloring material and a liquid medium, and reacts with the color ink by contact with the color ink.
According to still further aspect of the present invention, there is provided an ink-jet recording method comprising the steps of: (i) ejecting the aforementioned black ink toward a recording medium by applying energy to the black ink; and (ii) ejecting the aforementioned color ink toward a recording medium by applying energy to the color ink, wherein the steps are performed so that the black ink and the color ink form a contact state on the recording medium.
According to another aspect of the present invention, there is provided a recording unit comprising ink container portions containing each of the inks constituting an ink set and an ink-jet recording head for ejecting each of the inks supplied from the ink container portions by applying energy to the inks.
According to further aspect of the present invention, there is provided an ink cartridge comprising ink container portions containing each of the inks constituting an ink set.
According to still further aspect of the present invention, there is provided an ink-jet recording apparatus comprising: an ink container portion containing an ink set comprising at least a black ink and a color ink; and an ink-jet recording head for ejecting each of the inks supplied from the ink container portion by applying energy to the inks, wherein the ink set is the aforementioned ink set.
According to still further aspect of the present invention, there is provided an ink for ink-jet comprising: (a) a polyvalent metal salt, (b) a material selected from the group consisting of acids including amino groups and salts thereof, (c) a coloring material, and (d) a liquid medium.